If $5$ lunks can be traded for $3$ kunks, and $2$ kunks will buy $4$ apples, how many lunks are needed to purchase one dozen apples?
Explanation: One dozen apples is 12 apples, which costs $2\cdot3=6$ kunks (since 4 apples cost 2 kunks), which costs $5\cdot2=\boxed{10}$ lunks (since 3 kunks cost 5 lunks).